Cayman’s Glycolysis Cell-Based Assay Kit provides a colorimetric method for detecting L-lactate, the end product of glycolysis, produced and secreted by cultured cells. In this assay, lactate dehydrogenase catalyzes the reaction between NAD+ and lactate, yielding pyruvate and NADH. The NADH directly reduces a tetrazolium salt (INT) to a colored formazan which absorbs between 490 and 520 nm. The quantity of formazan produced is proportional to the quantity of lactate in the culture medium, and is thus an indirect measurement of glycolysis. This assay can be adapted to high-throughput screening to examine glycolytic regulators in a cell-based system. In addition, the non-invasive sampling leaves the cells intact and thus allows multiplex testing for additional markers.